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## Influence of nonionic surfactant on drop coalescence in a stirred tank

### Paulina Niewiarowska

#### Abstract

The influence of nonionic surfactant Tween 80 on toluene drop coalescence and breakage in a stirred tank is presented in this work. Surfactants have a tendency to adsorb at the interface, and lower the surface tension, thus preventing coalescence of the droplets. This work consists of two parts. The first part presents a review of the literature. It shows surface phenomena and the phenomena of breakage and coalescence of droplets in turbulent flow. In the second, experimental part, transient drop size distributions for different surfactant concentration and different impeller speed are measured. The results are presented as cumulative as well as differential volume fraction. Sauter diameter d32 dependence on time is also shown. The presence of Tween 80, decreases the rate of coalescence of droplets and increases breakage frequency. It also increases time, which is necessary to achieve the dynamic equilibrium between breakage and coalescence. Lowering the rate of coalescence is related to the interfacial tension gradient, which generates additional tangential stress and immobilizes drop surface. In the case of breakage, the presence of surfactant decreases stresses opposing droplet deformation.
Record ID
WUT0133fe095dde4b9b9e42b715242f0a9d
Diploma type
Master of Science
Author
Paulina Niewiarowska (FCPE) Paulina Niewiarowska,, Faculty of Chemical and Process Engineering (FCPE)
Title in Polish
Badanie wpływu niejonowego środka powierzchniowo czynnego na koalescencję kropel w mieszalniku
Supervisor
Wioletta Podgórska (FCPE/DCRED) Wioletta Podgórska,, Department of Chemical Reactor Engineering and Dynamics (FCPE/DCRED)Faculty of Chemical and Process Engineering (FCPE)
Certifying unit
Faculty of Chemical and Process Engineering (FCPE)
Affiliation unit
Department of Chemical Reactor Engineering and Dynamics (FCPE/DCRED)
Study subject / specialization
, Inżynieria Chemiczna i Procesowa
Language
(pl) Polish
Status
Finished
Defense Date
14-02-2012
Issue date (year)
2012
Pages
79
Internal identifier
DICHP-2120
Reviewers
Wioletta Podgórska (FCPE/DCRED) Wioletta Podgórska,, Department of Chemical Reactor Engineering and Dynamics (FCPE/DCRED)Faculty of Chemical and Process Engineering (FCPE) Robert Hubacz (FCPE/DPKT) Robert Hubacz,, Department of Process Kinetics and Thermodynamics (FCPE/DPKT)Faculty of Chemical and Process Engineering (FCPE)
Keywords in Polish
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Keywords in English
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Abstract in Polish
File
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Paulina_Niewiarowska_praca_magisterska.pdf
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Identyfikator pracy APD: 2887
urn:pw-repo:WUT0133fe095dde4b9b9e42b715242f0a9d